1. Field of the Invention
The present invention relates generally to coating compositions comprising an alkoxysilane, a polysiloxane, and a plurality of particles.
2. Background Information
Color-plus-clear coating systems, which involve the application of a colored or pigmented basecoat to a substrate followed by application of a transparent or clear top coat (clearcoat) over the basecoat, are typically used as original finishes for automobiles manufactured in the automotive OEM industry. These color-plus-clear systems possess outstanding appearance properties such as gloss and distinctness of image due in large part to the clearcoat.
Because the clearcoat is the outermost coating layer on such a coating system, it is susceptible to damage from numerous environmental elements. These elements include acidic precipitation, exposure to ultraviolet radiation from sunlight, high relative humidity and temperatures, and defects due to impact with small, hard objects resulting in chipping and scratching of the coating surface.
Typically, a clearcoat having a harder more highly crosslinked film may exhibit improved scratch resistance, but it is much more susceptible to chipping and/or thermal cracking due to embrittlement of the film resulting from a high crosslink density. A softer, less crosslinked film, while not prone to chipping or thermal cracking, is susceptible to scratching, water spotting and acid etch due to a low crosslink density of the cured film. There is, accordingly, a need for an improved clearcoat.